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By E. B. Olds

This paper describes the methods and costs of deepening the 3-compartment underground shaft in the Hooper Tunnel adit at the Bunker Hill & Sullivan Mining and Concentrating Company Crescent mine in the Coeur d'Alene mining region, 7 miles east of Kellogg, Shoshone County, Idaho. The work was done with the aid of a Defense Minerals Exploration Administration contract (No. Idm-E493, Docket No. DMEA-2764). Preparation for deepening the shaft was begun March 26, 1953, and sinking was completed May 27, 1954. The shaft, bottomed at 1,275.5 feet in 1939, was deepened to 3,276 feet, using mechanical mucking and intermediate pockets. A total of 50,349 man-hours was required to complete the work of sinking 2,000.5 feet, cutting 7 pump stations, and driving 2 pocket raises. The rate of advance was 7.1 feet of shaft per operating day, or 8.4 feet per day of actual sinking. The total direct cost for sinking was $205.20 per foot.

Jan 1, 1957

Isometric strength is defined as the capacity to produce force or torque with a voluntary isometric (muscle[s] maintain[s] a constant length) contraction. The key thing to understand about this type of contraction and strength measurement is that no body movement occurs during the measurement period. The tested person's body angles and posture remain the same throughout the test. Isometric strength has historically been the type most studied and measured. It is probably the easiest to measure and to understand. Some strength researchers feel that isometric strength data may be difficult to apply to some "real life" situations because in most real circumstances people are moving - they are not static. Other researchers counter that it is equally difficult to determine the speed of movement of a person or group of persons doing a job (each moves in his or her unique manner and speed across the links and joints of the body). Thus, dynamic strength test data collected on persons moving at a different speed and/or in a different posture from the "real world" condition will be just as hard to apply. In truth, neither is better - they are different measurements. Both researchers and users should collect and use data that they understand and that fits their application. Workplace Assessment When a worker is called on to perform a physically demanding lifting task, the external load produces moments - tendencies to produce motion, also called torques - about various joints of the body.(1) Often these moments are augmented by the force of gravity acting on the mass of various body segments. For example, in a biceps curl exercise, the moment produced by the forearm flexors must counteract the moment of the weight held in the hands as well as the moment caused by gravity acting on the forearm's center of mass. To perform the task successfully, the muscles responsible for moving the joint must develop a greater moment than the combined moments of the external load and body segment. It should be clear that, at each joint of the body, there is a limit to the strength that the muscle can produce to move ever-increasing external loads. This concept forms the basis of isometric muscle strength prediction modeling.(1) The following procedures are generally used with this biomechanical analysis technique. First, workers are observed (and usually photographed or video-taped) as they perform physically demanding tasks. For each task the posture of the torso and the extremities are documented at the time of peak exertion. The postures are then re-created using a computerized software package, which calculates the load moments produced at various joints of the body as the task is performed. The values obtained during this analysis are then compared to population norms for isometric strength obtained from a population of industrial workers. In this manner, the model estimates the proportion of the population

Jan 1, 1998

By K. L. Williams

The Bureau of Mines laboratory tested the response of a commercially available real-time aerosol monitor (GCA RAM-1) to various dusts. Monitor measurements were recorded, averaged, and compared with simultaneous gravimtric measurements of each test dust. Tests usually lasted several hours. The test dusts of various particle size distributions used included coal, limestone, and a commercially available test dust. For each particular dust, the monitor response was linear and correlated well with mass concentration over the range of about 0.5 to 10 mg/m3. The monitor can estimate a 2.0-/m3 respirable coal dust concentration within as little as 26 pct with 95 pct confidence. The monitor must, however, be calibrated with the dust to be measured because the instrument response is affected by the type of dust particle. The average monitor response to same mass concentration of coal dust was approximately twice the average monitor response to the same mass concentration of limestone dust.

Jan 1, 1984

By N. Grosland, G. Kopp, T. Hunstad, D. Wilder, M. Contratto, S. Rahmatalla, T. Xia

Chronic whole-body vibration exposure, as expected in large construction and mining vehicles, has been associated with neck and back pain and injury.1 While work has been done towards gaining a better understanding of the relationship between vibration and shock and muscle activity of the back musculature2, relatively little information regarding the activity of neck, shoulder and upper arm muscles is known. Today’s equipment designs must conform to domestic and international standards, however these standards do not specifically address the vibration exposure in the head and upper quarter. Further it is not well known how the control configuration within a vehicle (e.g. steering wheel versus arm controls) influences muscle voluntary and reflex activity levels. Greater muscle activity may lead to greater muscle fatigue – which in turn may be associated with greater risk of injury.2 Thus, muscle contractions needed to maintain static postures as well as those resulting reflexively should be considered during an analysis of seating position. Unfortunately, little is known regarding the influence of arm position on head and neck muscle function. The purpose of this study was to investigate the relative muscle activities of 5 neck, shoulder, and upper arm muscles during riding simulations of large construction equipment, using three different arm control options. Methods Five typical heavy equipment ride files were “played back” through a man-rated Servo Test 6-degree of freedom (dof) vibration system. Each ride was repeated using 3 seat and control configurations (steering wheel (SW), floor mounted arm-rest controls (FM), seat mounted arm-rest controls (SM)). Two trials were performed for each ride and seat control combination (each trial: 60 sec of 6-dof and 60 sec of vertical vibration). Five channels of surface electromyography (EMG) of the right-side cervical erector spinae muscles (neck extensors), sternocleidomastoid (neck flexor), upper trapezius (shoulder elevator), biceps brachii (elbow flexor) and triceps brachii (elbow extensor) muscles were collected throughout each ride (~ 2min) using pre-amplified (10x), 1 cm silver bar electrodes, with 1 cm fixed inter-electrode distances (Delsys, Inc). Further analog amplification was set at 10k (1k for one subject), and sampled at 1000Hz using a 12-bit DAQ card and Labview 7.1 software (National Instruments). A total of 7 right-handed male subjects were tested, but only 5 had complete EMG data sets to analyze for this sub-study. EMG was analyzed using root mean square (RMS, in mV) of 20 ms moving windows, and then averaged across the entire trial for a measure of mean total muscle activity (voluntary and reflexive). The muscle activity to maintain the static posture was estimated as the mean RMS EMG over a 1 sec interval just prior to and/or after completion of the ride. Repeated Measures ANOVAs were used to test for with-in subject differences using a = 0.05.

Jan 6, 2006

By J. L. Konchesky

The technical feasibility of gasifying powdered, noncoking, low-rank coal with steam in an externally heated tube has been demonstrated. The tube, 112 ft. of alloy-steel tubing shaped into a helix, served as an electrical conductor of electricity used for heating. The effects of the following variables were studied: Residence time of coal in reactor, average reaction temperature, steam concentration, and rank or geologic age of coal. Reaction pressure was maintained in the range 19-26 p.s.i.a. High carbon conversions and large yields of synthesis gas were obtained with low-rank coal. In one test, for example, about 88 pct. of the carbon in a subbituminous C coal was gasified at 1,910* F. with a residence time of 1 sec. The gas contained 58 pct. H2, 19 COD 15 CO, and 3 CH4; the yield was 30 cu. ft. (at 32' F. and 14.7 p.s.i.) of synthesis gas (CO + H2) per pound of dry coal.

Jan 1, 1960

By Peter G. Chamberlain

The surge in gold and silver prices during the 1970's attracted many new mining operators and has rekindled interest among experienced ones. With its low capital investment requirements and fast payout, leaching has attracted many operators--particularly those with small or low- grade deposits. Although in certain situations leaching offers many advantages over conventional mining methods, many operators are uncertain how these relatively new techniques should be implemented. Consequently the Bureau of Mines has prepared this circular to disseminate information on gold and silver leaching practices, techniques, and problem. Engineering data gathered from 26 operations indicate that most ores are leached in heaps following crushing and distribution on pads. Metal values are recovered from cyanide leach solutions using either zinc precipitation or charcoal adsorption. Potential problems that my hamper on block development of a leaching operation are poor percolation characteristics of the ore, calcium salt buildup, low temperatures, and solution losses. An extensive bibliography on gold and silver leaching is appended.

Jan 1, 1984

Objective: To identify and evaluate a permanent stopping to direct ventilation airflows in large-opening metal/nonmetal mines.

May 1, 2006

By N. Kumar Kittusamy

The purpose of this study was to assess the adequacy of the cab design and to determine the percentage of musculoskeletal symptoms among operators of mobile equipment used in mining and construction. A questionnaire was designed to assess demographics, work information, job history, and musculoskeletal symptoms in operators of heavy mobile equipment. Information concerning equipment included design of the seat/chair, levers, pedals, bothersome vibration, quality of ingress/egress from the equipment, proper preventative maintenance and repairs, and age of the equipment. The body regions that were evaluated included the neck, middle/upper back, low-back, shoulder/upper-arm, elbow/forearm, wrist/hand, hip, knee, and ankle/foot. Five hundred and eighty six operators completed the questionnaire. The results indicate that these workers are at risk for developing musculoskeletal disorders, and the need to quantify risk factors (i.e., whole-body vibration and static sitting postures).

Jan 6, 2006

By J. R. Ruark

Because of the importance of oil-shale reserves the Bureau or Mines resumed research investigations in this field beginning in 1944. The Bureau early decided to build a Large-scale demonstration plant to accomplish the dual purpose of obtaining design data and to produce crude shale oil for refining studies. Two 40-ton-Capacity batch N-T-U (Nevada-Texas-Utah) retorts were completed for this purpose in 1947. After a preliminary operation, the plant was used to investigate process variables of air rate, recycle gas rate, and shale particle size and crude. Correlations obtained from these variables are presented in this report. Researchers concluded that recycle gas was not necessary for efficient operation of the process. Short comings of the batch method of processing the oil shale are pointed out in the report. Several periods of prolonged production operations were carried out. During these periods, the retorts were operated to produce as much crude oil per day as possible. The lifetime operation of the N-T-U retorts was divides into three periods, namely, preliminary operation, process variable study, and production operation. During the preliminary operation, 187 runs were made with a total of 7,596 tons of raw shale used to produce 3,688 barrels of crude shale oil. During the process variable study, 179 runs were made with a consumption of 7,494 tons of raw shale and a production of 4,218 barrels of crude shale oil. The production operation consisted of 554 runs in which 22,457 tons of raw shale was used to produce 12,359 barrels of crude shale ail. The overall total for the lifetime operation of the retorts consisted of 920 runs with a total consumption of 37,547 tons of raw shale and a production if 20,265 barrels of crude shale oil.

Jan 1, 1956

By Kenneth L. Kreamalmyer

"The demand for open-hearth iron ore and the existence of suitable smelting facilities in the St. Louis area seemed to warrant investigation of several Missouri iron-ore deposits of the filled-sink type. Preliminary examinations were made in the autumn of 1944 by an engineer3/ of the Bureau of Nines, and in December of the same year funds were allotted for the exploration of these properties by churn drilling. Three properties, the Silver Hollow Bank and the Newbauer and Coleman properties, were drilled. Work was completed May 8, 1945.The Federal Geological Survey and the Missouri Geological Survey and Water Resources assisted in the project by determining the stratigraphy from drill cuttings and by mapping the drilled areas.The properties explored are in the hilly section of east-central Missouri and are connected by all-weather graveled roads with various shipping points of the St. Louis-San Francisco Railway system within 3 to 6 miles of each property.The Silver Hollow Bank, in sec., 8, T, 40 N., R. l W. Franklin County, Missouri, is in the Meramec State Game Reserve. The nearest town and shipping point is Sullivan, Mo„ which is 6 miles distant. The Newbauer property, in sec. 28, T. 41 N., R, 2 W., Franklin County, Missouri, is approximately 3 miles west of Stanton; The Coleman property, in sec. 14, T. 38 N., R. 3 W., Crawford. County, Missouri, is within a short hauling distance of the railway at Elayer, Mb. These are shown on figure 1.The region surrounding the explored areas contains a series of low-lying hills or ridges and narrow winding valleys drained by the Meramec River system. These hills seldom rise more than 200 feet above the valley floors, most of which are approximately 700 feet above sea level. Except for numerous small farms and a few small towns, the entire region is covered by a dense growth of timber and small brush. The St. Louis-San Francisco Railway system, U. S. Highway 66, and numerous all-weather State and county roads traverse the area."

Oct 1, 1945

By T. J. Ballard

Chromite deposits in the vicinity of Louise, Troup County, Ga., were studied y the Bureau of Mines from September 1, 1942, to March, 15, 1943. They are about three-fourths of a mile southeast of Louise and 8 miles northeast of La Grange, Troup County, Ga. The existence of chromite deposits in that area has been known for more than 75 years, but no active prospecting was done until World War I. Prospecting continued intermittently' until 1928. The Bureau became interested in the deposits in connection with its strategic minerals investigations during World War II. The chromite in these deposits occurs as grains ranging from "pin-head" size to 3/8-inch and occasionally 1 inch. Some of the material is magnetic, indicating the presence of magnetite. Of the 300 samples taken during the course of the project, 266 were analyzed. Tables showing the analyses accompany this report.

Jan 1, 1948

By Seth C. Scharfer

"As part of the Bureau of Mines effort to provide thermodynamic data for the advancement of mineral technology, the Gibbs energies of formation of MoS2 (molybdenite) and WS2 (tungsten disulfide) were determined with high-temperature galvanic cells employing stabilized Zr02 (zirconia) as the electro¬lyte. In the temperature range from 867 to 1,209 K, potential measurements were obtained for the cellPt, MoS2 , Mo02 , SO2 = 1 atm // Zr02 // 02 = 0.0112 atm, Pt, with the overall cell reactionMoS2(c) + 3 02(g, 0.0112 atm) = Mo02 (c) + 2 S02(g). (1)These results, combined with the best available values for Gibbs energies of formation (?G°f) of Mo02 (molybdenum dioxide) and SO2 (sulfur dioxide) from the literature, give the standard Gibbs energy of formation of MoS2, ?G°f, for the reactionMo(c) + S2(g) = MoS2(c) (2)?G°f = -96.681 + 43.76 x 10-3T±0.538 kcal/mole, (3)where temperature (T) is expressed in Kelvins.Similar measurements in the temperature range from 872 to 1,210 K were obtained for the cellPt, WS2 , W03 , SO2 = 1 atm // Zr02 // 02 = 0.0114 atm, Pt, with the overall cell reactionWS2(c) + 3.5 02(g, 0.0114 atm) = W03 (c)+ 2 S02(g). (4) Combination of these results with the best available data of ?G°f for W03 (tungsten trioxide) and SO2 from the literature gives the Gibbs energy of formation of WS2 in the temperature range from 872 to 1,210 K for the reactionW(c) + S2(g) = WS2 (c)(5)?G°f = -92.429 + 43.88 x 10-3T ± 0.280 kcal/mole. (6)A third-law analysis yields a standard enthalpy (?H°f) for the reaction298Mo(c) + 2 S(rh) = MoS2(c), (7)?H°f = -67.36±0.60 kcal/mole, (8)298where the standard states are pure crystalline MoS2 / and rhombic sulfur."

Jan 1, 1980

By E. P. Hayes

This report supplements the date contained in Bureau of Mines Information Circular 6156, "Special features of core drilling in the salt beds of Western Texas and New Mexico," by J. S. Wroth. That circular dealt with the drilling of the first 12 of the 24 potash tests made by the U. S. Bureau of Mines in cooperation with the U. S. Geological Survey; this report is concerned with the drilling of the last 12 tests. ACKNOWLEDGMENTS The writer is indebted to R. E. Heithecker, the Bureau of Mines engineer who had charge of the drilling of tests 13 to 17, for his well-prepared records on the drilling of these tests.

Jan 1, 1933

By Paul W. Johnson, Ralph C. Kirby, Frank A. Peters

A series of economic evaluations of processes for producing metallurgicalgrade alumina from low- grade aluminous materials is being conducted by the Bureau of Mines to determine the relative processing costs . The two processes considered in this evaluation are concerned with the recovery of alumina from clay through the formation of ammonium alum . In the first process , dehydrated clay is leached with ammonium bisulfate solution ; in the second process , clay is baked with ammonium sulfate and then leached with water containing a small quantity of sulfuric acid . After the alumina is dissolved by either of these methods , the iron is reduced to the ferrous state to avoid crystallization of ferric sulfate with the alum . The recovery of pure alum requires two crystallization steps . The alum crystals are then redissolved and precipitated with ammonia to produce alumina hydrate , which is calcined to a - alumina . These evaluations are based on published work , and the proposed plants are designed for a capacity of 1,000 tons of alumina per day . The estimated operating cost per ton of alumina for the bisulfate leaching process is $ 117.06 , and for the sulfate baking process , $ 109.26 . Using a Marshall and Stevens chemical equipment index basis of 240.0 , the estimated fixed capital costs , in the same order , are $ 158 million and $ 146 million . Under current economic conditions , these two processes are not competitive with the Bayer process for the production of alumina from bauxite . Since small improvements will not reduce costs sufficiently to approach competitive costs , future research work with these processes should be confined to areas likely to result in major cost reductions .

Jan 1, 1965

By Arno C. Fieldner, J. W. Paul, WALTER A. SELVIG

Many mine samples of coal are analyzed each year in the laboratories of the Bureau of Mines. The analyses are made in connection with investigations relating to fuels belonging to or for the use of the United States Government, the causes of accidents in coal mines, the geologic relations of coal beds, and the quality and the value of the coal and lignite in the public lands. The systematic collection and analysis of such samples in connection with fuel investigations was begun in 1904 at the Government fuel-testing plant at the Louisiana Purchase Exposition. and was under the direction of the United States Geological Survey for six years. Descriptions of the coal samples collected between the beginning of this work, July 1, 1904, and the transfer of the fuel-testing and mine-accident investigations to the Bureau of Mines,July 1, 1910, were compiled and published in Bureau of Mines Bulletin 22.' Descriptions and analyses of samples collected during the fiscal years 1911 to 1913 were published in Bureau of Mines Bulletin 85.2 Descriptions and analyses of samples collected during the fiscal years 1913 to 1916 were published in Bureau of Mines Bulletin 123.3 The present bulletin presents analyses and descriptions of samples collected during the fiscal years 1916 to 1919. In order that the material in this bulletin may be used to supplement that presented in Bulletins 22, 85, and ,123, the same plan of geographical classi- fication has been followed, the analyses and descriptions of the samples being grouped in alphabetical order according to the State, county, and town near which the mines or prospects sampled are situated.

Jan 1, 1922

By Office of Public Information

"The Bureau of Mines was established in the public interest to conduct inquiries and scientific and technologic investigations concerning mining and the preparation, treatment, and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve material resources and prevent their waste; to further economic development; to increase efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the Bureau of Mines to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, the Bureau reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminars; in reference books; and in other non-Bureau publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make the kind of list and index presented in this special publication both necessary and valuable.·This issue of the Bureau of Mines. List of Publications and Articles describes reports and articles published during the period January 1, 1985, to December 31, 1989. It supplements the 50-year list of Bureau publications issued from July 1, 1910, to January 1, 1960;1 the 50-year list of articles by Bureau authors published outside the Bureau from July 1, 1910, to January 1, 1960;2 the 5-year lists of publications and articles from January 1, 1960, to December 31, 1964,3 from January 1, 1965, to December 31, 1969,4 from January 1, 1970, to December 31, 1974,5 from January 1, 1975, to December 31, 1979;6 and from January 1, 1980, to December 31, 1984.7"

Jan 1, 1990

By Thomas J. Peters

The Snowbank study area, which had been proposed as Wilderness, lies about 5 air mi southwest of Cascade, Idaho, and about 60 air mi north of Boise. The eastern boundary of the north-south-elongate study area lies 1-to 2-mi east of Cascade Reservoir; the western boundary is contiguous, in part, with the western boundary of Valley county. The 8,200-acre study area is underlain by Cretaceous granitoid rocks of the Idaho batholith. Three prospects were found in or near the study area during a library and field search. Gold occurs at one 30-ft adit, but the gold-bearing structure appeared too narrow to contain resources. Two other prospects appeared essentially unmineralized. No evidence of geothermal activity was observed. Rock in the area is not potentially useful as dimension stone because it does not split into flat slabs. To be used as aggregate, the rock would require crushing and hauling to distant markets. One of 18 alluvium concentrate (placer) samples contained free gold, worth $1.07 per cubic yard of gravel (at a $350 per oz gold price). No alluvial bars were seen; deposits were too small to contain gold resources or be considered gravel resources.

Jan 1, 1993

By Bruce Cantrell, K. L. Rubow

"INTRODOCTIONMeasurement of the contribution of diesel exhaust to respirable aerosol in mine environments has become increasingly important because of current concerns over the occupational health effects resulting from exposure to diesel emissions. In response to this, the U.S. Bureau of Mines is developing and evaluating new sampling methods for measuring diesel aerosol in underground mines. Two such techniques are being studied by the Bureau, size selective sampling and Chemical Mass Balance (CMB) modeling. These techniques use measurable physical or chemical characteristics of a mine aerosol sample to infer the amount of diesel particulate material contained in the sample.Size selective sampling is being adapted for measurement of diesel aerosol by the Particle Technology Laboratory (PTL) of the University of Minnesota under sponsorship by the Bureau. 1 It is based on the premise that diesel and mineral dust aerosol can be physically separated by size and collected during sampling using inertial impaction. An independent effort by the National Institute for Occupational Safety and Health to develop a size selective sampling technique was also sponsored by the Bureau.The second technique, CMB modeling, is being developed by the Bureau as an alternative measurement technique to referee the results obtained using size selective sampling.3 It compares measured trace element ""finger prints"" of aerosol sources with similar profiles of mine aerosol samples. From these, the portions of the sample contributed by each source can be determined. Results of these investigations in underground coal mines have confirmed that diesel and coal dust aerosol are of different size and can be measured separately using size selective sampling techniques.A major difference in diesel usage among underground mines is the requirement for exhaust gas cooling systems in coal and gassy noncoal mines. Nongassy mines usually employ limited exhaust conditioning in the form of catalytic converters, which have limited effect on primary exhaust particulate. The cooling system in most general use in gassy mines is the water scrubber. This device has little effect on most of the gases but removes particulate material from the exhaust. 5 Because of this, exhaust aerosol characteristics in nongassy mines are expected to be different. To see if size selective sampling techniques can be used in such mines, the Bureau and the University of Minnesota conducted a second study in three metal and nonmetal mines, two nongassy and one rated as gassy."

Jan 1, 1990

By Robert G. Gibson, Joel D. Gibbons

Measurements and analyses were conducted of whole-body vibration aboard seven commercially available passenger and/or recreational vehicles: sedan; sport-utility vehicle (SUV); pickup truck; moving truck; motorcycle; all-terrain vehicle (ATV); and boat. The purpose of the testing was to measure and assess whole-body vibration exposure in a range of typical vehicle environments in order to gain understanding of typical exposure levels characteristic of activities of daily living. Vehicle models tested (and model year) were: Ford Taurus (1995); Jeep Cherokee Sport (2000); Toyota Tundra SR5 (2002); Ford F-350 (1997); Harley-Davidson Electra Glide Classic (2004); Yamaha Kodiak 400 4x4; and Steiger Craft Model 21 Montauk. All vehicles were tested with their standard factory-installed seats and were operated under a range of normal operating conditions and speeds typical of intended vehicle use. Methods The measurement, processing, analysis, and exposure assessment methods follow the guidance of generally accepted, national and international consensus standards relevant to the evaluation of whole-body vibration, including ISO 2631-1 [1] and ANSI S3.18 [2]. Seats were instrumented with low-mass triaxial accelerometers mounted in seat pads. Accelerometers used in the test are specified to have flat frequency response over the frequency range of 0.5 to 80 Hz, and all accelerometers were recently calibrated traceable to the National Institute of Standards and Technology (NIST). Seat pads were installed following guidance in the relevant standards [1, 2], with sensitive axes of the accelerometers following the standard coordinate system with respect to the seated occupant. (The x-axis represents fore-aft motion; the y-axis represents side-to-side motion; and the z-axis represents vertical motion with respect to the occupant.) Vibration data processing and analysis, including filtering, sampling, frequency-weighting, averaging, summation, and determination of basic and additional metrics followed procedures in the relevant standards [1, 2]. Digitized time series data were acquired and stored using a PC-based data acquisition system. Whole-body vibration exposure analyses were conducted via post-processing. During data processing, recorded periods of seat acceleration that were identified and verified as resulting from occupant-induced motion rather than vehicle motion were excluded prior to exposure analysis. The basic evaluation metric for whole-body vibration is the frequency-weighted root-mean-square (r.m.s.) acceleration, aw. The primary additional evaluation metric is the fourth-power

Jan 6, 2006

By Douglas D. Reynolds

Intense vibration can be transmitted to the hands and arms of workers who use hand-held percussive or vibrating devices, tools, and work pieces. Continued habitual exposure to vibration directed to the hands can cause patterns of various symptoms associated with hand-arm vibration syndrome (HVAS). The International Organization for Standardization (ISO) first published ISO 5349 in 1986.3 This standard specified methods for measuring and evaluating vibration directed into the hands from hand-held vibrating devices, tools, and work pieces. The American National Standards Institute (ANSI) published ANSI S3.34 the same year.1 This standard was modeled after ISO 5349-1986 and specified methods for assessing exposure to hand-arm vibration. The Parliament of the European Union has issued the European Union Human Vibration Directive-2002/44/EC, which specifies vibration daily exposure action values (DEAV) of 2.5 m/s2 and daily exposure limit values (DELV) of 5.0 m/s2. These values have generally been accepted by medical experts, scientists, and engineers in governmental agencies, research institutions, and industry in the USA and other countries.2 When they are achieved, they will reduce the potential for the development of symptoms related to HAVS among workers exposed to hand-arm vibration. Significant improvements in measurement and analysis instrumentation, miniature and subminiature accelerometers, and medical diagnostic and assessment protocols have being introduced since 1986 when ANSI S3.34 was first published. In response to these improvements and the introduction of the EU Human Vibration Directive, ANSI Working Group S2.39 developed the revision to ANSI S3.34, which has now been published as ANSI S2.70-2006.2 Method ANSI S2.70 specifies the use of the hand-arm vibration measurement procedures outlined in ISO 5349, Parts 1 and 2.2,4,5 It requires the measurement of ISO frequency-weighted acceleration values in three mutually orthogonal axes of vibration. These values are then vectorially added to obtain the vibration total value, ahv: [ ] where ahwx, ahwy, and ahwz are the measured r.m.s. ISO frequency-weighted acceleration values in the x, y, and z directions, respectively. If multiple vibration exposure events are experienced during a work day, the overall vibration total value is obtained from: [ ] where ahvi is the vibration total value of the ith operation, Ti is time duration in hours of the ith operation, n is the total number of operations, and T is total time in hours associated with the n

Jan 6, 2006